1. Field of the Invention
The field of the invention relates to apparatus to measure gravity. The field of the invention also relates to methods of operation of the apparatus to measure gravity. The field of the invention further relates to apparatus adapted to perform measurements of gravity from within a borehole in the earth. The field of the invention also relates to methods of operation of apparatus adapted to perform measurements of gravity from within the borehole in the earth.
2. Description of the Prior Art
It is well known in the geological sciences that measurements of gravity within a borehole could be used to locate and quantitatively identify the amount of gas present in a hydrocarbon bearing reservoir. However, the present state-of-the-art apparatus do not provide sufficiently accurate measurements of gravity in boreholes to be widely used on a routine commercial basis. Further, the present state-of-the-art apparatus are not capable of performing measurements rapidly enough, or fast enough, for routine commercial services. For example, please refer to W. M. Telford, L. P. Geldart, R. E. Sheriff, and D. A. Keys, "Applied Geophysics", Cambridge University Press, Cambridge, reprinted in 1981, page 803. It is also well known to researchers at Gas Research Institute (GRI) located in Chicago, Ill. that present devices to measure gravity within boreholes are generally inadequate for routine widespread commercial operations. GRI's present standard publicly available scientific papers and reports on gravity measurements are incorporated herein in their entirety by reference herein.
For the purposes of this application, standard geophysical terms are used such as those appearing in the following references, entire copies of which are incorporated herein by reference: (a) John T. Dewan, "Essentials of Modern Open-Hole Log Interpretation", PennWell Publishing Company, Tulsa, Okla., 1983; (b) editor, "Cased Hole Log Interpretation Principles/Applications", Schlumberger Educational Services, Houston, Tex., 1989; (c) and Robert D. Langenkamp, "The Illustrated Petroleum Reference Dictionary", Third Edition, PennWell Publishing Company, Tulsa, Okla., 1985.
At the time of the filing of the application herein, the applicant is unaware of any prior art that is particularly relevant to the invention.